高手帮忙看看这段代码错在哪里。

Question

以下代码总是在m_pD3D->CreateDevice这里失败。
   
    
    HRESULT InitD3D(HWND hWnd)
      {
if(NULL==(m_pD3D=Direct3DCreate9(D3D_SDK_VERSION)))
{
MessageBox(NULL,L"Failed to create m_pD3D!",L"Error",MB_OK);
return E_FAIL;
} D3DPRESENT_PARAMETERS d3dpp;
ZeroMemory(&d3dpp,sizeof(d3dpp));
d3dpp.SwapEffect=D3DSWAPEFFECT_DISCARD;
d3dpp.BackBufferFormat=D3DFMT_UNKNOWN; if( FAILED( m_pD3D->CreateDevice( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd,
                                  D3DCREATE_MIXED_VERTEXPROCESSING,
                                  &d3dpp, &m_pD3DDevice ) ) )
{
MessageBox(NULL,L"Failed to create m_pD3DDevice!",L"Error",MB_OK);
return E_FAIL;
} return S_OK;
     }